1. Technical Field
The present invention relates to a driving circuit for driving a capacitive load which apply a drive signal to an actuator to eject a liquid. For example, the invention is suitable for a liquid ejecting-type printing apparatus which ejects a minute liquid from a nozzle of a liquid ejecting head and forms a minute particle (dot) on a printing medium, thereby printing a predetermined character or an image.
2. Related Art
As an example of a liquid ejecting apparatus, there is a known ink jet printer which ejects an ink (liquid) toward a recording medium from a nozzle provided in a head. Generally, a nozzle row having multiple nozzles arranged in a predetermined direction is formed in the head, for example, there is a known serial head method in which the head relatively moves in a direction in which a scanning direction of the head intersects a transportation direction of the recording medium and ejects an ink to print an image in a width of the nozzle row. As disclosed in JPA-2011-5733, there is also a known line head method in which nozzles are disposed in a row shape in a direction intersecting a transportation direction of a recording medium and an image is printed when the recording medium passes therebelow.
JP-A-2011-5733 discloses an exemplification in which a secondary filter consisting of one capacitor C and a coil L is used as a smooth filter, without specifying which type of the coil L needs to be used.
A coil used in smoothing an amplification modulation signal from a digital power amplification circuit generally tends to be great in heat generation and a loss, and thus, selection of a coil which can prevent heat generation and heat loss from occurring is a major disadvantage in designing a liquid ejecting-type printing apparatus. Particularly, in a printer, since an amplification modulation signal at a high frequency such as a MHz order is used in order to obtain a printed matter having sufficient quality and resolution, it is difficult to use a method of selecting a coil adopted in other electronic apparatuses (for example, an ordinary audio apparatus uses a frequency of approximately 32 kHz to 400 kHz) in a printer as it is.